I'm on Enhertu as well for recurrence of uterine serous carcinoma. HER 2 Positive. I started in May with a CA 125 of 74..after 3 treatments CA 125 down to 22 and after 4 treatments now 16....I will have a PET scan in August to see exactly what's going on. Side effects from treatment have been manageable no nausea some chemo fog but have been able to continue all normal activity. pilates, pickleball and work. I'm told that there is no end date with enhertu so I am hopeful that I will continue to tolerate it well and that it will keep an agressive cancer at bay !